Abstract
Most applications using network connection services require information to be transferred
within specific constraints (or Quality of Service). Parlay enables applications to access
functionality of underlying networks while preserving network integrity. Connection service
functionality of underlying networks is currently provided to applications by Parlay in the
Call Control and Data Session Control SCFs. Parlay does not however provide access to
the QoS functionality of connection services although this functionality may be provided by
networks. This report presents the design, specification and simulation of a QoS framework
for connection services provided by Parlay. The QoS framework provides applications with
access to the QoS functionality of connection services in the underlying networks. The design
is divided into 3 parts (or models): the object model (defines the objects that make up
the QoS framework), the information model (deals with how objects specify QoS and mappings
between different QoS specifications), and the interaction model (defines how objects
interact). A formal, technology-independent specification of the QoS framework is presented
using UML. The specification is composed using the three parts of the design. A simulation
of the QoS framework presented in this report is also described to validate the framework.
The simulation is a multi-threaded, distributed CORBA application implemented in JAVA
(Java SDK version 1.5) and is based on the UML specification of the QoS framework. Details
about the simulation design and implementation are summarised in this report. The QoS
framework provides per-application, per-connection QoS support for Parlay’s connection services,
supports existing and future Parlay connection services, follows existing Parlay design
paradigms, and co-exists with and makes use of existing and future Parlay infrastructure.
Parlay guidelines relating to permitted changes are followed strictly in the design of the QoS
framework, which ensures the backward compatibility of Parlay if the QoS framework is
added to the Parlay API. All Parlay design guidelines are also followed to allow for the easy
integration of the QoS framework into the Parlay API. The simulation validates that the
design of the QoS framework is: complete (in terms of specification), realistic, compatible
with a standard Parlay implementation (JAVA and CORBA), and scalable (easy integration
of new connection services).